The present invention relates to a capsule for preparing a beverage such as coffee in a beverage production machine.
Single-use beverage capsules are very popular because they provide a fresh tasting beverage quickly, conveniently and in a clean fashion. Therefore, certain beverage capsule systems propose to extract a coffee liquid from roast and ground coffee ingredients contained in a capsule that opens under pressure when a sufficient amount of water has filled the capsule. More particularly, the pressure of liquid increases in the capsule before the delivery face of the capsule opens thereby conferring a good quality of extraction.
In order to provide a thorough interaction between the ingredients, e.g., ground coffee and hot water, it is desirable to delay the release of the beverage through the delivery side. Many different solutions already exist.
In particular, NESPRESSO® capsule system, as described in EP0512470B1, is based on the principle that an extraction face of the capsule is torn against relief and recessed elements of a capsule holder in the beverage production machine. The extraction face tears at the location of these relief elements and/or recessed elements on reaching the breaking stress to enable the liquid, e.g., coffee extract, to be removed after extraction of the coffee under a certain positive pressure. EP0512468B1 also describes a capsule which is adapted for such extraction process and device.
EP0179641 relates to a sachet comprising two sheets forming with a filtering web material the chamber for the ingredients. The two sheets are sealed at the bottom of the sachet to form a bottom seam that breaks under pressure of the beverage.
U.S. Pat. No. 4,853,234 relates to a beverage package wherein the outlet is opened automatically, in use, by the pressure of beverage. The pressure of beverage builds up in the outlet channel and causes the seal formed between a top portion and a rib to break. The beverage thus flows over the rib into a collection channel which funnels the beverage to form a stream which can be collected in a cup or other receptacle.
In both EP0179641 and U.S. Pat. No. 4,853,234, the flow of beverage leaving the capsule experiences a high velocity because the direction of the flow acting against the breakable seal is oriented in the direction of the outlet. Therefore, as soon as the seal is broken, the beverage leaves straightforwardly and rapidly the cartridge. As a result, when the cartridge is opened, the pressure in the capsule drops, hence the interaction between coffee and water becomes poor. Furthermore, the flow of beverage is given a too high velocity when leaving the capsule. Hence, the beverage can create splashes if it is not dampened properly before reaching the cup. Thus, improvements over these prior art devices are desirable.